The present invention relates to an electronic throttle valve control apparatus suitable for use in a car engine and more particularly to a car throttle valve control apparatus suitable for controlling a throttle valve by using a motor.
As a conventional car throttle valve control apparatus, an electronic throttle valve control apparatus has been known in which for adjustment of intake air flow sucked into an engine, a throttle valve attached to an intake manifold is controlled by a motor.
Generally, as described in, for example, JP-A-8-303285, for control of the opening of the throttle valve, the opening of the throttle valve is detected by means of, for example, a potentiometer connected directly to a rotary shaft of the throttle valve under the control of a microcomputer and the detected opening is inputted to the microcomputer through an A/D converter to perform operational control which makes the detected opening coincident with a target opening.
A technique as described in, for example, JP-A-6-54591 has also been known, according to which current flowing through a motor for rotating a throttle valve is chopper-controlled by means of, for example, an H-bridge chopper circuit comprised of power MOS FET's, the current flowing through the motor is detected and fed back to a microcomputer and a result of the feedback control operation is delivered out of the microcomputer in the form of a PWM signal to control the opening of the throttle valve.